Although the present invention may be useful in any number of devices, one type of device requiring an electrically wired connection is a closed cycle cryogenic cooler (hereinafter “CCCC”), which is commonly used to cool devices such as infrared detectors. One such example of a CCCC may be seen in U.S. Pat. No. 5,822,994 (“the '944 patent”), the entire disclosure of which is incorporated herein by reference. Specifically, the CCCC of the '994 patent comprises a compressor section incorporating reciprocating pistons which are mechanically/pneumatically driven by a prior art coil system.
As can be seen in FIG. 1, an example of the prior art coil system 8 of the compressor of the '994 patent incorporates a number of compression springs 10 to position motor coils 12 in a floating configuration. While such floating configurations generally reduce negative impacts when side loading the compressor section, these configurations further require a number of additional springs 14 on the opposite axial side of the coil 12 to restore force balance. Moreover, the system incorporates an electrical conduit network 18 in which the electrical current enters the same axial side of the system in which the current is returned. Since rotation may misalign the spring seats (not shown) and cause electrical disconnection of conduit network 18, a guide pin 16 is thus required to restrict rotation of the coil 12. A clocking guide (not shown) is also required to accommodate for the relative movement of the springs 10, 14 and ensure compressor functionality.
Another example of a prior art coil system can be seen in FIG. 2 and is generally indicated by reference number 8′. Coil system 8′ incorporates a symmetric pair of flexure springs 10′ to position motor coils 12′ in a concentric manner. While this configuration reduces the part count of other prior art coil configurations, springs 10′ are generally manufactured from electrically conductive material having a significant radial stiffness. Coils 12′ must also be mounted in a certain fixed position within the compressor so as to both prevent the need for a clocking guide and allow for incorporation of electrical conduit network 18′ (in which electrical current enters and returns on one axial side). Such mounting of coils 12′, however, hinders coil functionality since the coils are unable to float and self-align within the compressor. Moreover, assembly of system 8′ is complex due to coils 12′, springs 10′, and conduit network 18′ being required to be mounted with a certain degree of accuracy for these components to function properly.
There therefore remains a need for a system comprising a coil configuration that reduces the number of assembly components found in prior art floating coil configurations but without the loss of coil rotation and functionality accompanying prior art symmetric coil configurations, as well as other needs.